1. Field of the Invention
The present invention relates to a roller chain capable of suppressing noise and vibration which are generated upon abutment of the chain with a sprocket.
2. Description of the Related Art
When a roller chain engages a sprocket, the outer peripheral surface of the roller collides with the tooth surface of the sprocket, and an end face of the roller strikes against an inside surface of an inner plate of the chain, resulting in generation of a noise. In the roller chain disclosed in Japanese Utility Model Publication No. 15067/90, which intends to prevent the said noise, a roller and elastic rings of a rectangular section positioned in a sandwiching relation to the roller are provided axially in series on a bushing which is fitted in inner plates of the chain, the elastic rings being larger in diameter than the roller. When the chain engages a sprocket, the resulting collision sound is absorbed by an elastic deformation of the elastic rings.
However, there arises the problem that the elastic rings when deformed come into abutment with roller edges and the resulting stress concentration on end faces causes breakage of the elastic rings in an early stage. Further, since the area of contact between the elastic rings and the inner plates is large, the resulting frictional resistance is also large, so that the rotation of the elastic rings is obstructed. As a result, the elastic rings undergo a local wear, which eventually leads to breakage of the elastic rings. Thus, the chain no longer exhibits the noise preventing effect.